I have a found a pinhole leak in a elbow joint (not in the seal, the hole is actually in the joint) that is squirting a small steam of water (less that 3"). Its on a lateral run of pipe in the second floor attic. I assume the pipe is under pressure because its squirting out - not dripping.

Is there any silicone sealant or epoxy that will safely seal a pinhole size leak, or does the joint need to be cut out and replaced?

I ran into this same problem but the pipe was really hard to reach. Replacing the elbow would have meant moving a joist out of the way. So what I did was get a scrap piece of pvc pipe just slightly larger, cut a square patch from it, warmed it up with a heat gun, using a wad of rags to keep from burning my hand, I wrapped the patch against the leaky area till it cooled off, thus matching the profile. After that I glued my newly formed patch with pvc cement.

That was over 10 years ago and I haven't heard back from them, presumably because it worked.

Note that Glenn's advice is best, but I just thought I'd share this story.

Yep! Replace it ! If you're real good you can couple it in both directions with standard glue in couplers . Fit it dry, clean both the coupler both the pipe ends (with proper cleaner) then apply glue to all surfaces both pipe ends and coupler ends the shove em together and twist the coupler a 1/4 turn to seat parts. hold inplace for a minute sothey won't back off and your done. repeat process at the other end of repair. If you're timid about trying this you can also buy snap in couplers at Lowes but they are quite a bit more in expense.

I ran into this same problem but the pipe was really hard to reach. Replacing the elbow would have meant moving a joist out of the way. So what I did was get a scrap piece of pvc pipe just slightly larger, cut a square patch from it, warmed it up with a heat gun, using a wad of rags to keep from burning my hand, I wrapped the patch against the leaky area till it cooled off, thus matching the profile. After that I glued my newly formed patch with pvc cement.

That was over 10 years ago and I haven't heard back from them, presumably because it worked.

Note that Glenn's advice is best, but I just thought I'd share this story.

Merry Christmas!

I like this solution. A professional plumber might not do it because it might be difficult to guarantee the work, but my gut feel is that a pipe patched like this would be better than the original. I might have tried tape, maybe the kind of thick black tape that seals to itself or the tape specially designed for plumbing repair. I'm sure professional plumbers wouldn't be too keen on that idea either.

I ran into this same problem but the pipe was really hard to reach. Replacing the elbow would have meant moving a joist out of the way. So what I did was get a scrap piece of pvc pipe just slightly larger, cut a square patch from it, warmed it up with a heat gun, using a wad of rags to keep from burning my hand, I wrapped the patch against the leaky area till it cooled off, thus matching the profile. After that I glued my newly formed patch with pvc cement.

That was over 10 years ago and I haven't heard back from them, presumably because it worked.

Note that Glenn's advice is best, but I just thought I'd share this story.

Merry Christmas!

I like this fix! -- I was waiting for someone to suggest Billy's(from TV) fix with the epoxy putty...

I hate to say it but I have not seen a building code where INTERIOR use of PVC pipe for pressure piping is legal for EXACTLY the reason you mentioned.
I have also had a customer for whom I was doing electrical work blame me for a crack in a PVC pipe feeding a spa he installed in an upstairs room. I took a camwera back into the crawlspace to take some pix and in the light of the flash and on the pic it was clear as day that he had mice who were chewing on the PVC and severely weakened it.

The white PVC pipe from Lowes et all is for outdoor use only. Even schedule 40. I hope you can repair the leak but be advised it is still a dangerous situation.

Wow Gizmologist:
North Carolina must have changed their plumbing code. I know that in the Kentucky code and the National code, PVC is acceptable for cold water supply; they do like to see CPVC for hot water lines though.
Kentucky just recently began to allow PVC under a concrete slab for cold water supply, whereas before they wanted nothing but copper without any joints under a slab.
Glenn